This is the 40th year of this highly successful research Training Program in Rheumatology at Massachusetts General Hospital (MGH) and Harvard Medical School (HMS), supported by training grant T32 AR07258. The goal of this program is to train MD, MD/PhD and PhD post-doctoral fellows for independent investigative careers in rheumatology research. Of the 58 graduates of the program that were directly supported by this training grant, many now have faculty appointments in academic medical centers, including holding leadership positions at major institutions as Deans, Scientific Directors, and Division Chiefs. Our program centers on our outstanding clinical Rheumatology fellowship and our strong basic, translational, clinical science and clinical epidemiology research programs. The MGH Rheumatology T32 Training Program is situated within a vibrant, technologically-innovative research environment. Our program provides supervised laboratory, clinical and health outcomes research under the guidance of accomplished faculty members, as well as structured training in rheumatology, immunology, clinical trials, epidemiology, biostatistics and ethical issues through courses or conferences. The basic science research focus of the program is the study of the immunopathogenesis of rheumatic disease. Areas of particular interest include autoimmunity, innate immunity, leukocyte trafficking, inflammation, infectious causes of rheumatic diseases and the microbiome, systems immunology, fibrosis, and stem cell biology. Disease areas of particular interest include rheumatoid arthritis, lupus, scleroderma, Lyme, gout, systemic vasculitis and IgG4-related disease. The clinical science research program focuses on population and health care sciences in rheumatic diseases. This application requests 4 training positions that will be allocated to trainees who are committed to at least 2 to 3 years of research training. The candidates will be recruited from the MGH Rheumatology fellowship and from post-doctoral trainees already working in the laboratories of faculty mentors. Seventeen faculty members primarily from the MGH Rheumatology Unit and its affiliated Center for Immunology & Inflammatory Diseases (CIID) participate in this T32 Training Program. Faculty mentors were carefully chosen based on their track record of publications, grants, collaboration, mentoring, and mutual interest in rheumatology, immunology and health care sciences. The Training Program leverages many of the research centers at MGH, including the Ragon Institute, Cancer Center, Center for Regenerative Medicine, and Mongan Institute. The MGH provides an outstanding training environment and is home to the largest hospital-based research enterprise in the U.S., with an annual budget of $912 million in 2017 comprising more than 8,500 researchers. Opportunities at Harvard, including course work and the NIH- funded Harvard Clinical and Translational Science Center, as well as the Broad Institute provide additional resources for trainees. In sum, in this renewal application represents a cohesive, integrated, high-quality Training Program in basic, translational, clinical and health outcomes research in the rheumatic diseases.